Most people, even I, would tell you "because you might experience good moments for which the suffering would be worth it, because you can be dead for an eternity but live only once so might as well do everything you can" etc You've probably heard stuff like that a million times. And you know, I stand by it when a person can turn their life around for the better but that's not always the case and you shouldn't have to continue living if you don't want to and if you don't care about getting like one good moment amongst months of suffering. Also I think that people should live or die for their own sake, other people wanting you to stay (which sounds like to be the case) shouldn't be the deciding factor because they don't experience the things you do.
I hope what I said makes sense, I know you're probably mostly asking those questions as vent.